Anything around us and in the entire universe can be classified as either matter on energy.
The Particle Theory of Matter:
1. Matter is made up of tiny particles (Atoms & Molecules)
2. Particles of Matter are in constant motion.
3. Particles of Matter are held together by very strong electric forces
4. There are empty spaces between the particles of matter that are very large compared to the particles themselves.
5. Each substance has unique particles that are different from the particles of other substances
6. Temperature affects the speed of the particles. The higher the temperature, the faster the speed of the particles.
The particle theory of matter explains the following scientific phenomena:
Pure substance are homogeneous (one phase - one unique kind of particle)
Physical Changes - Melting, Evaporation, Sublimation, Dissolving.....
Characteristic Physical Properties - Density, Viscosity, Electrical & Thermal Conductivity
According to particle theory, all matter is composed of tiny particles called protons, neutrons and electrons. These tiny particles make up the atom. Atoms, ions and molecules are also particles. In a gas these particles have a large amount of space between each other. In liquids the particles are closer together. In solids they are even closer together.
Kinetic Theory of Matter
The Kinetic Theory of Matter is the statement of how we believe atoms and molecules, particularly in gas form, behave and how it relates to the ways we have to look at the things around us. The Kinetic Theory is a good way to relate the 'micro world' with the 'macro world.'
A statement of the Kinetic Theory is: 1. All matter is made of atoms, the smallest bit of each element. A particle of a gas could be an atom or a group of atoms. 2. Atoms have an energy of motion that we feel as temperature. The motion of atoms or molecules can be in the form of linear motion of translation, the vibration of atoms or molecules against one another or pulling against a bond, and the rotation of individual atoms or groups of atoms.3. There is a temperature to which we can extrapolate, absolute zero, at which, theoretically, the motion of the atoms and molecules would stop. 4. The pressure of a gas is due to the motion of the atoms or molecules of gas striking the object bearing that pressure. Against the side of the container and other particles of the gas, the collisions are elastic (with no friction). 5. There is a very large distance between the particles of a gas compared to the size of the particles such that the size of the particle can be considered negligible.
Since light, electromagnetic radiation, is required to see an object and light hitting an object gives it energy, as soon as one is able to see an object at absolute zero, it is not at absolute zero anymore from the new energy. Any other means of detection would add energy to the material at absolute zero. An object at absolute zero would be as hard to keep as a lump of antimatter. What would you keep it in? Practically, we can cool something down to temperatures approaching absolute zero, but we cannot get to that theoretical point, nor can we achieve temperatures below that point. There is no such thing as a temperature below absolute zero.
The Kinetic Theory of Matter does not, and is not intended to, take into account the energy of atoms due to excitation of electrons as you might see in glowing neon in a neon light or the bright redness of molten iron. In fact, objects cooler than molten iron and less excited than electrified neon will give off electromagnetic radiation, but that is another story.
In the view at this level, it is useful to look at atoms as if they were close to the hard little balls that Dalton considered. With this very mechanical view of atoms and molecules, we are losing some important facts to get an instructive thought on matter.
Brownian motion
Brownian motion (named after the Scottish botanist Robert Brown) is the seemingly random movement of particles suspended in a liquid or gas or the mathematical model used to describe such random movements, often called a particle theory.
Diffusion
Diffusion refers to the process by which molecules intermingle as a result of their kinetic energy of random motion. Consider two containers of gas A and B separated by a partition. The molecules of both gases are in constant motion and make numerous collisions with the partition. If the partition is removed as in the lower illustration, the gases will mix because of the random velocities of their molecules. In time a uniform mixture of A and B molecules will be produced in the container.
The tendency toward diffusion is very strong even at room temperature because of the high molecular velocities associated with the thermal energy of the particles.
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